Well this thing has been running for a few years now so I'm sure someone has that data

A snapshot of one year's participation in that specific period isn't too relevant to what we are discussing, because it doesn't track sustained future contributions by those same users.

That's a good point. Wonder if they're be open to adding something like that...?

Maybe suggest that in an issue on that stats tracking repo?

In theory they are. In practise the lack of a test dataset - and the lack of access to their dataset - means it's virtually impossible for a third party to make any significant contribution to the data processing code.

Such an effort would have to start with them voluneering a test dataset and/or schema.

I have asked - https://github.com/MattIPv4/hacktoberfest-data/issues/5